Control apparatus for electric locks for railway track switches



Dec. 29, 1953 w. R. BAKER ET AL 2,664,500

CONTROL APPARATUS FOR ELECTRIC LOCKS FOR RAILWAY TRACK SWITCHES 3 Sheets-Sheet 1 Filed June 25, 1949,

INVENTORS. Baker and Hob eff Hasensfe el THEIR ATTORNEY 1953 w. R. BAKER ET AL 2,664,500

CONTROL APPARATUS FOR ELECTRIC LOCKS FOR RAILWAY TRACK SWITCHES Filed June 23, 1949 5 Sheets-Sheet 2 THEIR A T TOR/Vi Y Dec. 29, 1953 w. R. BAKER ET AL CONTROL APPARATUS FOR ELECTRIC LOCKS FOR RAILWAY TRACK SWITCHES 3 Sheets-Sheet 5 Filed June 25, 1949 INVENTORS'. ether and I Hosensteei THEIR flTTOH'NEY Patented Dec. 29, 1953 CONTROL APPARATUS FOR ELECTRIC LOCKS FOR RAILWAY TRACK SWITCHES Warwick R. Baker and Robert M. Rosensteel, Wilmington, N. 0., assignors to Westinghouse Air Brake Company, a corporation of Pennsylvania Application June 23, 1949, Serial No. 100,896

13 Claims.

Our invention relates to control apparatus for electric locks for railway tracks switches. More specifically, our invention relates to means for releasing an electric lock for a railway track switch either promptly or upon the lapse of one or another measured period of time according to trafiic conditions and according to the distance of the location of the switch in advance of a signal which governs tramc movements over the switch.

Operation of a railway track switch may be effected from a central or a distant point such, for example, as an interlocking tower or a dispatchers office, or it may be effected locally. Operation of a railway track switch which is eiiected locally is usually accomplished by manual power applied through a manually operable switch operating lever direct to suitable mechanism for moving the switch between its normal and reverse positions.

Manually operable switch operating levers are equipped with padlocks in order to prevent movement of the switches by unauthorized persons. However, a railroad employee who has a switch padlock key might become confused or might misunderstand or forget an order or timetable regulation and might therefore open a switch padlock for moving the associated switch while it is unsafe to do so. If, for example, a trainman should erroneously reverse a switch for a train to move from an auxiliary track when a train is approaching at high speed on a main track in which the switch is located, there would probably be a collision between the two trains.

In order to protect against manual operation a of a railway track switch while traffic conditions are such that it is unsafe for the switch to be operated, an electric lock, in addition to the switch padlock, may be employed. Heretofore, no provision has been made for having different lengths of release time for the electric locks for two or more switches in a block over which traffic movements are governed by the same signal. Also, no provision has been made, before applicants invention, for releasing the electric lock for a switch upon the lapse of a given period of time after a train on a main track in which the switch is located passes the signal which governs trafiic movements over the bloclr in which the switch is located, and for releasing the electric lock for the same switch upon the lapse of a longer period of time when the switch is to be reversed for a train to move over the switch from an. auxiliary track onto the main track.

An object of, our invention is.the-.provision of:

means for releasing the electric lock for a switch promptly after a train passes a signal for the block in which the switch is located, if the switch is a short distance in advance of the signal, and for releasing a second switch in the same block which is a longer distance in advance of the signal upon the lapse of a longer period of time after the train passes the signal.

Another object of our invention is the provision of means for releasing the electric lock for a switch upon the lapse of a given measured period of time after the switch padlock for the switch is removed preparatory to reversing the switch for a train to move from an auxiliary track to a main track in which the switch is located, and for releasing the electric lock for the same switch either promptly after a train on the main track enters the block in which the switch is located or upon the lapse of a measured period of time which may be shorter than the given measured period of time according to the distance the switch is located in advance of a signal which governs trafiic movements over the switch.

A feature of our invention for accomplishing these objects is the provision of a directional stick relay controlled in part by a track relay for a short track section which is located immediately in advance of a signal which governs traffic Y movements over a signal block in which one or more switches are located. In our invention, electric locks for switches which are located a short distance, less than 500 feet, for example, in advance of a signal are controlled directly by front contacts of the directional stick relay, and are therefore released promptly after a train, on a main track in which the switch is located, passes the signal. Also, in our invention, a time element device which has a relatively short operating time may be controlled by a front contact of the directional stick relay. Switches located between 500 and 3000 feet, for example, in advance of a signal are controlled by this time element device. A time element device which has a longer operating time is used for releasing each of the switches when a train movement is to be made from an associated auxiliary track to the main track, and is also used for releasing a switch when a train on the main track passes the signal for governing traflic movements over the switch, if the switch is more than 3000 feet, for example, in advance of the signal.

We shall describe three forms of apparatus embodying our invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a.

diagrammatic View showing one form of apparatus embodying our invention, in which a stretch of main railway track includes a signal block divided into a short section, designated by the reference character AT, adjacent and in advance of a signal, designated by the reference character IS, for governing trafilc movements over the block, and a longer second section VI in advance of the short section; in which an approach section GT is shown in the rear of the signal; in which a directional stick relay ISR is arranged to become energized when a train passes the signal onto the short section, for effecting energization of an electric lock AWL for a first switch A in the second section a relatively short distance in advance of the signal; in which a time element device ITER becomes energized for eifecting energization of an electric lock CWL for a second switch C in the second section a longer distance in advance of the signal, upon the lapse of a given measured period of time after a train on the main track passes the signal; and in which the time element device ITER becomes energized for effecting energization of one or both the electric switch locks AWL and CWL upon the lapse of the given measured period of time after the padlock for either switch is removed preparatory to reversing the associated switch for a train to move from an associated auxiliary track onto the second section.

Fig. 2 is a diagrammatic view showing a modified form of apparatus embodying our invention, in which two time element devices are employed, one of which, designated ITER, has a relatively longer time of operation than the other which is designated Z'I'ER; in which energization of the electric lock AWL. for the first switch A in the second section is controlled by the directional stick relay ISR, as in Fig. l; in which the first time element device I'IER, which has the longer time of operation, is controlled by a back contact of the directional stick relay ISR and by a contact which is closed when a trafiic responsive decoding relay iHR for the second section is deenergized while a track relay ATR, for the first section is energized; in which the second time element device ZTER, which has, the shorter time of operation, is controlled by a front con.- tact of the directional stick; relay 153; in which the second switch C is controlled by the; second, time element device ZTER when a train on the main track passes the signal; and in which one orboth switches may be controlled by the first time element; device l'lTER, as in Fig. 1, when either or both switches are to be reversed; for a train to move from an associated auxiliary traclt onto the second section.

Fig. 3v is a diagrammatic view showing a modified form of the apparatus of Fig. 2, also embodying our invention, in which the first section 4RT in the block is within interlocking limits in an interlocking plant, and the second section A l-T is outside of interlocking limits; and in which the signal Res which governs trafic movements over the block is controlled by a lever 4V in aninterlocking machine, and therefore normally displays the stop indication; in which the first time element device AQTER becomes energized when a track relay AATR for the second section becomes deenergized, and the second time element device Z TER is controlled by a front contact of a stick relay fiZSlEt, as in Fig. 2;; and in which the switches are controlled by these time element devices, as in Fig, 2

Similar reference characters, refer to, similar parts in each of the views.

Referring first to Fig. 1 of the drawings, a stretch of main railway track is shown, over which trains normally move in the direction indicated by the arrow, which we shall assume is the eastbound direction. The stretch of main track includes a signal block divided by insulated joints 2 into the short section AT adjacent, and in advance of, signal IS which governs trafiic movements over the block, and the longer second section, designated by the reference character IT, in advance of section AT. The stretch of track also includes the app-roach section, designated by the reference character OT, in the rear of signal IS.

Each of the sections AT and OT is provided with a track circuit including a suitable source of current, such as a battery 3, connected across the rails adjacent one end of the section, and a track relay, designated by the reference character R preceded by the reference character for the associated section, connected across the rails adjacent the opposite end of the section. Section IT is also provided with a track circuit including a suitable source of current, such as a battery 3, connected across the rails adjacent one end of the section through a contact 5 of a coding device, designated by the reference character CT. Device CT is connected directly across terminals B and N of a suitable source of current, such as a battery Q, so that device CT is con stantly energized, and therefore its contact 5' repeatedly closes and opens at a frequency which may, for example, be 180 times per minute. A code following track relay, designated by the reference character lTR, is connected across the rails adjacent the opposite end of section VI.

Signal IS may be of any suitable design such, for example, as the well-known scarchlight type.v Signal iS governs eastbound traffic movements on the main track over section AT onto section IT.

A track switch A is shown in section lT a distance in advance of signal IS, which we shall assume is, less. than 500 feet, for example. A second track switch C is also shown in section IT a distance in advance of signal IS, which we shall assume is more than 3000 feet, for example.

Each of the switches A and C is provided with an electric switch lock, designated generally by the, reference, character WL, preceded by the reference character for the associated switch. Each of the electric switch locks AWL and CWL may be. of any suitable design, such, for example, as. the type of electric switch lock disclosed and claimed in a copending application, of common ownership, for Letters Patent of the United States, Serial No. 721,028 filed by Herbert L. Bone, George L. Temple, and John W. Logan, Jr. on January 9, 1947, for Electric Locks.

Each of the switch locks AWL and CWL includes. an associated manually operable device, shown as. a lever V, which has a normal position n, an intermediate position 0- and a reverse position r. Lever V is locked in its normal posh tion n. by a switch padlock. When the padlock is removed, lever V' may be moved to its intermediate position 0, in which a. locking member 6: engages a dog 1. Further movement of lever V toward its r position is prevented until dog I hasv been lifted, by an electromagnet 8, out of engagement with looking member 6.

Switches A and C are operated by manual power applied through switch operating levers AV" and CV, respectively, to switch mechanisms AW and CW, respectively. Levers AV and CV are locked in their normal position for retaining-switches A and C, respectively, in their normal positions, in whichthey are shown in the drawings, while switch lock levers V are in their n or 0 position. Levers AV and CV are released for operating switches A and C, respectively, only when lever V of switch lock AWL or CWL, respectively, is in its 1' position.

Lock contacts 9, I0, and II, operated by lever V, are normally open, when lever V is in its n position, but become closed upon movement of lever V to its 0 position, and remain closed when lever V is moved on to its 1* position. Lock contact 9, upon becoming closed, completes a shunt path across the rails of section IT, causing relay ITR to be deenergized.

Energization of each of the lock magnets 8 is effected by an associated lock control relay, designated by the reference character WAR preceded by the reference character for the associated switch. Each of the lock control relays AWAR and CWAR is normally energized over a control circuit which includes conductors 65 and 66, through contact 24 of relay OTR, and through the front point of contact 23 of a relay IHR, which is closed only while the track relays for sections AT and IT are both energized. Relay CWAR is also controlled by contacts 25 and 21 of a time element device shown as a time element relay ITER, either in response to a train entering the signal block for signal IS, or in response to movement of lever V of switch lock CWL from its 71. position to its 0 position. Relay AWAR is also controlled by contacts 25 and 21 of relay I'I'ER in response to movement of lever V of switch lock AWL to its 0 position, and is controlled by contacts 38 and 39 of directional stick relay ISR.

Trafiic responsive decoding relays, designated by the reference characters IFPR and I HR are controlled by relay AIR and by code following track relay ITR. An asymmetric unit, designated by the reference character if is connected across the winding of each of the relays IFPR and I HR in order to make these relays slow in releasing, so that they will retain their contacts in the picked-up position during the open periods of the front and back points, respectively, of contact l8 of relay ITR, while relay ITR is responding to coded current supplied to the opposite end of section IT. Asymmetric units t may be of the well-known copper oxide half-wave rectifier type.

Time element device ITER is .controlled by contact 29 of relay IFPR and the back point of contact 23 of relay I HR.

Directional stick relay' ISR is controlled by relays ATR and [HR so that it becomes energized when a train on the main track passes signal IS onto section AT, and remains energized while the train occupies sections AT and IT.

Signal Is is controlled in part by a contact 22 of relay IHR, and normally displays a proceed indication.

- Referring next to Fig. 2 of the drawings, switch A is assumed to be less than 500 feet in advance of signal IS, as in Fig. 1, but switch C is here assumed to be between 500 and 3000 feet in advance of signal IS.

In Fig. 2, relay AWAR is controlled the same as in Fig. l, but relay CWAR is controlled by the second time element device ZTER, in response to a train on the main track passing signal iSonto the signal block. Relay CWAR is controlled otherwise as in Fig. 1.

' Relay ZTER is controlled by a circuit which includes the front point of a contact 3'! of re-:

lay ISR, and relay ITER is controlled by a cira cuit which includes a back point of contact 31 of relay l SR. Relay I 'I'ER closes its front contacts upon the lapse of a given measured periodof time afterit becomes energized. Relay ZTER closes its front contacts upon the lapse of a measured period of time which is shorter than the given measured period of time. It follows that, when a train on the main track passes signal IS onto the signal block, relay CWAR may become energized upon the lapse of a shorter period of time than is required for relay CWAR to become energized when a train is to be moved from an auxiliary track over switch C onto section IT.

Referring now to Fig. 3, the first section 4RT of. the signal block is here within, interlocking limits of aninterlocking plant, and the second section A4T. is outside of interlocking limits. Switch A is assumed to be less than 500 feet in advance of signal R48, and switch C is assumed to be between 500 and 3000 feet in advance of r signal R4S, similarly to switches A and C in advance of signal IS in Fig. 2. A portion of another railway track X is shown, which intersects section 4RT.

Signal R46 may be of any suitable design such, for example, as the well-known searchlight type. Signal R4S governs eastbound traffic movements on the main track over a signal block which includes sections 4R'I and NH.

A signal of the searchlight type comprises various parts which we have grouped together for signal R4S, and designated as a signal mechanism R im. Signal mechanism R4m comprises an optical unit, which has a single lamp E, and an operating element comprising a member l4 mounted to rotate in both directions as con trolled by a signal winding l 3. Attached to mem ber I4 for rotation therewith between a normal position to the right and a reverse position to the left are three colored filters or roundels designated by the reference characters G, R, and

Y which may be of the colors green, red, and yellow, respectively. Member [4 is biased to a mid stroke or intermediate position, to which it moves when the associated signal winding [3 is deenergized. When signal winding I3 is energized'by current of the polarity which we shall term normal polarity, as shown in the drawing, member I4 is moved to the right-hand position. For convenience in illustration, lamp E is shown above the roundels, but it is to be understood that lamp E isnactually located directly behind one-of the roundels according to the position of the member l4. Roundel G, R, or Y is moved in front of lamp E according as memher !4 is moved to its right-hand position, its

intermediate position, or its left-hand position, respectively. -When lever 4V is moved to its r position, signal R48 is controlled to display a clear proceed indication, in which roundel G is placed in front of lamp E,

Operatively connected with member I4 is a circuit controller comprising two movable contact fingers l5 and 16. With signal R4S displaying the stop indication on account of its winding I 3 being deenergized, as shown in the drawing, movable contact finger I5 engages a fixed con tact element [5a, and movable contact finger l6 engages a fixed contact element l6a.

A signal of the type described is disclosed and claimed in Letters Patent of the United States No. 1,864,224 granted June 21, 1932, to Wesley B. Wells for Light Signals.

A stop signal repeater relay, designated by the reference character APR, is controlled by the circuit controller for signal R43, so that relay APR is normally energized while signal RQS is displaying the stop indication, but becomes deen-- ergizes when mechanism R4m is operated to a proceed position. Relay 4PR is made slow releasing by an asymmetric unit t connected across the windingof the relay..

An approach locking stick relay designated by the reference character AASR, associated with the signal RAS, is normally energized when relays 4PR and OTR are energized, and becomes deenergized when relay APR becomes deen'ergized when signal R48 is controlled to display aproce'ed indication. Relay 4ASR has a second p'ckup circuit which includes a back contact 43 of relay HRTR. and has .a third pickup circuit which includes a contact 44 of -a time element device shown as a relay ATER. Relay 4TER is controlled by contact 4| of relay APR and by the back-point of contact 45 of relay EASR.

Relays AWAR and CWAR. are here controlled by relay 4ASR instead of by the relay OTR as in 'Fig. '2, but arecontrolled otherwise as shown in Fig. 2.

Having described, in general, the arrangement and control of the various parts of apparatus 'embodyingour invention, we shall now describe the circuits and operation in detail.

As shown in the drawings, all parts of the apparatus are in the normal condition, that is, track sections OT, AT, and IT shown in Figs. 1 and 2, and sectionsOT, ART, and AAT shown in Fig. 3, are unoccupied, and therefore track relays GTR, ATR, ITR, IRTR, and AA'IR are energized; signal is, shownin Figs. 1 and 2, is energized and displays a clear proceed indica tion, and signalR lS, shown in Fig. 3, is deenergized, and is thereforedisplaying a stop indication; each of the switches A and C is in its normal position; each of the electric lock levers V is locked in its '71 position by an associated switch padlock and therefore contacts 9, l0, and H of each of the electric switch locks AWL and CWL are'open; relays IFPR and IHR, shown in Figs. 1 -an'd'2,relays AWAR and CWAR, shown in all figures, and relays AQFPR, A lHR, AASR, and APR, shown only in Fig. 3, are energized; and relays 'iSRa-nd ITER, shown in Figs. 1 and2, relay 'ZTER, shown in Figs. 2 and'3, relays 4ZSR, ATER, and AATER, shown in Fig. 3, are deenergized.

The circuit for relay lFPR s'hown in Figs. "1 and 2,'passcs from terminal B, throughthe front point of contact I! of relay ATR, 'front point of contact 18 of relay vITR, and the winding of relay IFPR to terminal 'N. The circuit by which relay l'HiR. is energized, as shown in Fig. 1, passes from terminal B, through the-front point of contact i -.of relay ATR, back point of contact I8 of relay ITR, contact 26 of relay lTER, contact 2-! of relay JFPR, and the Winding of relay IHR to terminal N. The circuit for relay IHR,-as shown-in-Eig. 2, is the same as the circuitshown in Fig. 1, except that it includes contact l9'of relay ZTER, in addition to the contacts shown in-Fig. l. The-circuit by which signal l S is controlled to display a clear proceed indication ineludes contact 22 of relaylHR.

EEhecircuit by which relays AWAR and CWAR are'energized, as shown'in Figs. land 2, passes 8 from terminal B, through the front pointof-contact 23 of relay l-HR, contact 24 of relay O'IR, conductor (iii, windings of relays AWA-R and CWAR in multiple with each other, conductor 68, contact 26 of relay OTR, and the front point of contact 28 of relay IFPR to terminal N.

We shall assume that, with apparatus embodying our invention as shown in Fig. 1, aneastbound train on the main track enters section OT. Contacts 24 and 260i relay OTR therefore open the circuit just traced for :relays AWAR and C-WAR, causing these relays to become deenergized.

Vieshall assume further that a trainmanfrorn a train on an associated auxiliary track removes the padlock from lever Vrofswitch lock AWL before the train on the main track'arrives at signal lS, so that contacts 9, Iii, and H of switch lock AWL become closed. Contact 9 of switch .lock AWL, upon becoming closed, completesa shunt across the rails of section IT, causing track relay IZIR to become deenergized. With relay 1TB deenergizecl, its, contact l8 becomes opened at the front point, so that relay lFPR. is deenergized. With relay IFE R. deenergized, relay IHR is .in turn also deenergized because contact 2| ofrelay "IFPB, is opened, causing signal ES to display the stop indication because contact 22 of relay IHR :is

opened.

With relays IHR and 'sIFPR vde'energized, time element relay iTER becomes :energized :by a :circuit passing from terminal B, through the'back point of contact 23 oftrelay lI-IR, winding of :relay FREE, and contact as .ofi'rielay lFRR to terminal N. Upon the lapse of a measured'period of time after its energiz'ingcircuit becomes closed, relay 'ITER closes its contacts 225 and2*'l, thereby completing a second-circuit for energizing-relays AWAR and. CWAR, this :circuit'passingifrom terminal B, through the'back 'pointofconta'ct .23 of relay il-IR, contact 25 of relay l-FER, conductor 65, windings of relays AWAR and CWARin multiple with each other, conductor 66, contact '2? of relay ITER, and'the -back point of contact 28 of relay i-FPR to terminal N. Relay AWAR, upon becoming energized by its pickup circuit through its upper control winding, as shown in Fig. 1 of the accompanying drawings, closes a. retaining circuit including its'lower windingas shown in the drawing, this circuit passing from terminal B, through contact it of lock AWL-contact 32 of relay AWAR, the lower winding of relay AWAR, contact 33 of relay AWARyand contact H of lock AWL to terminal 'N.

With relay AWAR energized, the'lock control winding 8 for lock AWE-a ls energized by'a circuit passing from-terminal B, through contact lll of lock AWL, contact '32 of relay AWAR, lock control winding 8, contact 33 of relay AWAR, and con-tact i I of-lock AWL to terminal N. Winding of lock AWL, upon becoming -'energized,-liftsits dog 7 out of engagement with the associated lock-- ing member 5, so that lever V'of lock AWL can be moved to its r positiomthereby releasing the operating lever AV for switch A.

If, insteadof removingthe padlookfrom lever V of lock AWL, a trainman of 'a train'on an auxiliary track removes the padlock from lever'V of lockCWL before a train onthe main track arrives at signal ES, signal is will be controlledtodisplay :the 1 stop indication and control winding 8 oflockCWL will become energized similarly to the manner just described in connection with lock AWL.

Ifthe padlock hasnot been removedifrom lever V of either switchilock ANVLnr CWL beforethe ace'ac'oo train on the main track arrives at signal IS, the train will pass signal IS, and will deenergize relay A'IR, causing relay IHR to become deenergized, which in turn causes signal IS to display the stop indication as previously described. Relay IHR, on account of being slow releasing because of asymmetric unit it connected across its winding, retains its contact 3s closed at the front point for a brief period of time after contact I! of relay ATR opens at its front point. During this brief period, directional stick relay I SR will become energized by its pickup circuit passing from terminal B, through the back point of contact I1 of relay ATR, front point of contact 36 of relay II-IR, and the winding of relay ISRto terminal N. Relay I SR, upon becoming energized, completes its stick circuit passing from terminal B, through the back point of contact I! of relay ATR, con tact 37 of relay ISR, and the winding of relay ISR to terminal N. Contact 36 of relay II-IR, upon becoming closed at its back point, completes a second stick circuit for relay ISR, this circuit passing from terminal B, through the back point of contact 36 of relay II-IR, contact 3! of relay ISR, and the winding of relay ISR to terminal N.

If, now, a trainman removes the padlock from lever V of switch lock AWL, relay AWAR will become energized by a second pickup circuit passing from terminal B, through contact ID of lock AWL, contact 38 of relay I SR, lower winding of relay AWAR, as shown in the drawings, contact 39 of relay ISR, and contact I I of lock AWL to terminal N. With relay AWAR energized, lock control winding 8 of switch lock AWL will first be energized in multiple with the lower winding of relay AWAR, through contacts 38 and 39 of relay ISR, and will then be energized through contacts 32 and 33 of relay AWAR as before, and willlift its dog I out of engagement with locking member 6, z

so that lever V can be moved to its r position.

Lever V of lock AWL, upon being moved to its 7' position, unlocks the manual switch operating lever AV, so that switch A can be moved to its reverse position. If the train is moving faster than a slow speed such, for example, as miles per hour, there will not be time for switch A to be operated before the train arrives at switch A, since switch A is assumed to be less than 500 feet in advance of signal IS. Switch A can, however, beoperated promptly after the train has passed it, because relay AWAR is energized by its circuit including contacts of relay ISR.

1 As soon as relays iHR and IF'PR become deenergized by the train passing signal IS, relay ITER will become energized by its circuit prel viously traced. Relay CWAR will then become energized upon the lapse of a measured period of time, as previously described. .FQI. relay .ITER,-a time. element relay is sele'cted which has an operating period of time longer than it will take a train traveling at a slow speed such, for example, as 15 miles per hour, to move from signal I S to switch C. A train'which is traveling faster than 15 miles per hour will therefore arrive at switch C before relay ITER can close its contacts 25 and 21.

We shall next assume that, with apparatus embodying our invention modified as shown in Fig. 2, an eastbound train enters section OT, and that a trainman removes the padlock from lever V of switch lock AWL before the train arrives at signal IS. Relay ITR will therefore become deenergized, as previously described, because contact 9 of switch lock AWL will complete a shunt path across the rails of section 1T.

16 With relay ITR deenergized, its contact I 8 will become opened at the front point, so that relay IFPR, and, in turn, relay II-IR, will become deenergized. Relay ITER will then become energized by a circuit passing from terminal B, through the back point of contact of relay IHR, back point of contact a? of relay ISR, winding of relay ITER, and contact as of relay IFPR to terminal N. Contacts and 21 of relay ITER will become closed upon the lapse of a measured period of time for energizing relays AWAR and CWAR as previously described.

We shall now assume that all parts of the apparatus, modified as shown in Fig. 2, are again in the normal condition, and that an eastbound train passes signal IS, causing relay ISR to become energized as previously described in connection with Fig. 1. Relay ZTER will then become energized by a circuit passing from terminal B, through the back point of contact 36 of relay IHR, front point of contact 3'! of relay ISR, the winding of relay ZTER, and contact 49 of relay IFPR to terminal N. Upon the lapse of a measured period of time which is less than the period of time required for operation of relay ITER, contacts and El of relay ZTER become closed for energizing relay CWAR for releasingelectric lock CWL sooner than if switch C were controlled only by relay ITER, as shown in Fig. 1. The circuit by which relay CWAR is energized passes from terminal B, through the back point of contact 23 of relay I HR, contact 30 of relay ZTER, conductor '65, winding of relay CWAR, conductor E56, contact 3! of relay ZTER,

and the back point of contact 28 of relay IFPR, to terminal N.

In the modified form of apparatus embodying our invention as shown in Fig. 3, relay iASR is normally'energized, both a pickup and a stick circuit being closed. The pickup circuit which is closed passes from terminal B, through contact 4| of relay iPR, contact 42 of relay OTR, and the winding of relay lASR to terminal N. The stick circuit passes from terminal B,

through contact dl of relay tPR, front point of contact 45 of relay lASR, and the winding of relay IASR to terminal N. Relay AAFPR is energized by current passing from terminal B, through the front point of contact 46 of relay AATR, and. the winding of relay AdFPR to terminal N. Relay A li-IR is energized by current passing from terminal B, through the back point of contact 46 of relay A iTR, contact il of relay A4FPR, and the winding of relay Ail-IR to terminal N. Relays AWAR and CWAR are normally energized by a circuit passing fromterminal B, through the front point of contact A8 of relay A4HR, contact 59 of relay GRTR, contact 50:01 relay IASR, conductor 65, windings ofrelays AWAR and CWAR in multiple with each other, conductor 65, contact 53 of relay 4ASR, contact 56 of relay l-RTR, and the front point of contact 51' of relay AtF'PR to terminal N.

We shall assume that, with the apparatus arranged as shown in Fig. 3, an eastbound train on the main track arrives on section OT, and that a leverman moves lever 4V to its r position for clearing signal R lS. With lever 4V in its 1* position, signal winding I3 will be energized by its circuitpassing from terminal B, and including contact I2 of lever 5V, and winding I 3.

of signal R48 to terminal Member I l of mechanism R im will then be rotated toward the right for moving roundel G in front of lamp Contact I5-I5a of signal R48 will therefore 11 be opened, causing relay GPR to become deenergized. Relay fiASR will therefore, in turn, also be deenergized, so that its contacts 513 and 53 will open the circuit traced for relays AWAR and CWAR, causing these relays to also be deenergized.

If the leverman then decides to return signal R48 to the stop position before the train on the main track passes signal RAS, he will return lever 4V to its n position, deenergizing winding 13. Member M of mechanism Rem will therefore return to its normal position in which it is shown in the drawing, so that the circuit controller again completes the circuit for energizing relay 4PR. Time element relay ATER will therefore now be energized by a circuit passing from terminal B, through contact 4| of relay lPR, back point of contact 45 of relay 4ASR, and the winding of relay tTER to terminal N. Upon the lapse of a measured period of time, relay ATER will close its contact 44, thereby completing a second pickup circuit for relay dASR, which is the same as the first pickup circuit traced for this relay except that it includes contact 44 of relay dTER instead of contact 42 of relay OTR.

If, instead of returning signal ms to the stop position before the train passes signal Res, the leverman waits until after the train passes signal R48, and then returns signal R45 to its stop position, relay AASR will become energized by a third pickup circuit passing from terminal B, through contact 4| of relay @PR, contact 43 of relay ARTR, and the winding of relay GASR to terminal N.

When the train enters section lRT, deenergizing relay ARTR, relay 4ZSR becomes energized by its pickup circuit passing from terminal B, through contact 58 of relay lRTR, front point of contact 59 of relay A4HR, and the winding of relay AZSR to terminal N, similarly to the manner in which relay SR becomes energized as described in connection with Fig. 1. If a trainman now removes the padlock from lever V of switch lock AWL, relay AWAR will become energized by a circuit which includes contacts 6! and 52 of relay AZSR, similarly to the mannor in which relay AWAR becomes energized by a circuit including contacts of relay IFR, as described in connection with Fig. 1. Relay ZTER will also becom energized by an obvious circuit including contact 63 of relay GZSR. Upon the lapse of a measured period of time, relay CWAR will become energized by a circuit passing from terminal B, through the back point of contact 48 of relay A4HR, contact of relay ZTER, conductor 65, winding of relay CWAR, conductor 66, contact 55 of, relay ZTER, and the back point of contact 5'! of relay AAFPR to terminal N,

If, with the apparatus arranged as shown in Fig. 3, a trainman removes the padlock from lever V of switch lock AWL or switch lock CWL before a train on the main track passes signal R48, relay AATR will becom deenergized, so that relay .A'iF-PR will also become deenergized, and in turn relay A lHR will be deenergized. Relay A lTER will then be energized by a circuit passing from terminal 13, through the back point of contact 48 of relay A-lHR, winding cf relay A4TER, and contact 3 3 of relay AAFPR to terminal N. Upon the lapse of a measured period of time, which is longer than the time required for operation of relay ZTER, relays AWAR and CWAR will become energized by a circuit passing from terminal B, through the back point of contact 68 of relay AGHR, contact 52 of relay i2 A4TER, line conductor 65, the winding of relay AWAR in multiple with the winding of relay CWAR, conductor 66, contact 54 of relay AtTER, and the back point of contact 5'! of relay A iFPR to terminal Although w have herein shown and described only a few forms of apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, a stretch of main railway track including a signal block, a signal for governing traffic movements over said main track onto said block, a track switch in said block a short distance in advance of said signal, a second track switch in said block a longer distance in advance of said signal, an electric lock for each of said switches each of which when deenergized locks the associated switch in its nor mal position, a directional stick relay energized in response to a train on said main track passing said signal onto said block, a stick circuit for then retaining said directional stick relay energized in response to said train on said block, means controlled by a front contact of said stick relay for energizing the electric lock for said first switch, a time element device, a contact of said time element device which becomes closed upon the lapse of a measured period of time after said time element device becomes energized, means for energizing said time element device in response to a train on said block, and means controlled by said contact of said time element device for energizing the electric lock for said second switch.

2. In combination, a stretch a railway track including a signal block, a signal for governing traffic movements over said track onto said block, a track switch in said block a short distance in advance of said signal, a second track switch in said block a lon er distance in advance of said signal, an electric lock for each of said switches each of which when deenergized locks the associated switch in its normal position, directional means operated in response to a train on said track passing said signal onto said block, stick circuit means for then retaining said directional means in its operated condition in response to said train on said block, means responsive to operation of said directional means for energizing the electric lock for said first switch, and time element means operated in response to a train on said block for effecting energization of the electric lock for said second switch upon the lapse of a measured period of time after a train enters said block.

3. In combination, a stretch of railway track including a signal block, a signal for governing traflic movements over said track onto said block, a track switch in said block a short distance in advance of said signal, a second track switch in said block a longer distance in advance of said signal, an electric lock for each of said switches each of which when deenergized locks the associated switch in its normal position, directional means operated by pickup circuit means in response to a train on said track passing said ignal onto said block, stick circuit means controlled by said train on said block for then retaining said directional means in its operated condition as long as said train occupies said block, means including said directional means in its operated condition for efiecting energization of the electric lock for said first switch, and means responsive to a train on said block for effecting energization of the electric lock for said second switch upon the lapse of a measured period of time after the train enters said block.

4. In combination, a stretch of railway track including a signal block divided into a first and a second section, a signal for governing traffic movements over said first section and then onto said second section, a stick relay controlled to become energized only if said second section is unoccupied when a train enters said first section and. then to remain energized while said train occupies said second section, a track switch in said second section, an electric lock which when deenergized lockssaid switch in its normal position, and means controlled by a front contact of said relay for energizing said electric lock.

5. In combination, a stretch of railway track including a signal block which comprises a first portion between said signal and a switch and a second portion in which said switch is located, a signal for governing trafiic movements onto said block, directional means operated in response to a train on said track passing said signal onto said first portion of said block only if said second portion is unoccupied, means responsive to occupancy of said second portion of said block by said train for then retaining said directional means in its operated condition, an electric lock which when deenergized locks said switch in its normal position, and means responsive to said directional means in its operated condition for energizing said electric lock.

6. In combination, a stretch of main railway track including a signal block which comprises a first portion between said signal and a switch and a second portion in which said switch is located, a signal for governing traffic movements on said main track onto said block, directional means operated in response to a train on said main track passing said signal onto said first portion of said block only if said second portion is unoccupied, means responsive to occupancy of said second portion of said block by said train for then retaining said directional means in its operated condition, an electric lock which when deenergized locks said switch in its normal position, means responsive to said directional means in its operated condition for energizing said electric lock, and manually controllable tim element means for efiecting energization of said electric lock preparatory to operation of said switch for a train to enter said block from an auxiliary track.

7. In combination, a stretch of main railway track including a signal block, a signal for governing traffic movements onto said block, a track switch in said block, directional means operated in response to a train on said track passing said signal onto a first portion of said block between said signal and said switch, means responsive to occupancy by said train of a second portion of said block in which said switch is located for then retaining said directional means in its operated condition, an electric lock which when deenergized locks said switch in its normal position, means responsive to operation of said directional means for energizing said electric look, a second track switch in said block farther from said signal than said first switch, a second electric lock which when deenergized locks said second switch in its normal position, time element means, and manually controllable means for energizing said time element means for eiiecting 14 energization of said first and second electric locks preparatory to operation of the corresponding switch for a train to enter said block from a first or a second auxiliary track respectively.

8. In combination, a stretch of railway track including a signal block, a signal for governing trafiic movements onto said block, a track switch in said block, directional means operated inresponse to a train on said track passing said signal onto a first portion of said block between said signal and said switch, means responsive to occupancy by said train of a second portion of said block in which said switch is located for then retaining said directional means in its operated condition, an electric lock which when deenergized lock said switch in its normal posi tion, means responsive to operation of said directional means for energizing said electric lock, a second track switch in said block farther from said signal than said first switch, a second electric lock which when deenergized locks said second switch in its normal position, time element means, and means controllabl manually and in response to a train on said block for energizing said time element means for effecting energization of said first and second electric locks.

9. In combination, a stretch of railway track including a signal block, a signal for governing trafiic movements over said track onto said block, a track switch in said block a short distance in advance of said signal, a second track switch in said block a longer distance in advanc of said signal, an electric lock for each of said switches each of which when deenergized locks the associated switch in its normal position, means responsive to a train on said track passing said signal onto said block for effecting energization of the electric lock for said first switch, means responsive to a train on said block for eiiecting energization of the electric lock for said second switch upon the lapse of a measured period oi time after the train enters said block, and trafiicresponsive means for energizing both of said electric locks if said block is unoccupied and if said track is also unoccupied a given distance in the rear of said signal.

10. In combination, a stretch of railway track including a signal block which comprises a first portion between said signal and a switch and a second portion in which said switch is located, a signal for governing traflic movements onto said block, directional means operated in response to a train on said track passing said signal onto said block only while said second portion of said block is unoccupied, means responsive to occupancy of said second portion of said block by said train for then retaining said directional means in its operated condition, an electric lock which when deenergized locks said switch in its normal position, means responsive to operation of said directional means for energizing said electric lock, manually controllable time element means for efiecting energization of said electric lock preparatory to operation of said switch for a train to enter said block from an auxiliary track, and means responsive to trafic conditions on said track for effecting energization of said electric lock if said block is unoccupied and if said track is unoccupied a given distance in the rear of said signal.

11. In combination, a stretch of railway track including a signal block, a signal for governing trafiic movements onto said block, a track switch in said block, directional means operated in response to a train on said track passing said signal 155 onto said block, an electric lock which when do energized locks said switch in its normal position, means responsive to operation of said directional means for energizing said electric look, a second track switch in said block farther from said signal than said first switch; a second electric lock which when deenergized locks said second switch in its normal position, time element means, means controllable manually for energizing said time element means for effecting energization of said including a signal block divided into a first and g a second section, a signal for governing trafic movements over said first section and then onto said second section, a stick relay controlled to become energized when a train enters said first section and then to remain energized while said train occupies said second section, a track switch in said second section, a second track switch in said second section farther from said signal than said first switch, an electric lock for each of said switches each of which when deenergized locks the associated switch in its normal position, a traffic responsive relay energized when said first and second sections are clear but deenergized when either of said sections is occupied by a train or is otherwise shunted, means controlled by a front contact of said stick relay for effecting energization of the electric lock for said first switch, a time element device, means controlled by back contacts or said stick relay and said traific responsive relay for energizing said time element device, a second time element device, means controlled by a front contact of said stick relay for energizing said second time element device, manually controllable means associated with each of said electric locks for shunting the rails of said second section preliminary to unlocking the associated switch, means controlled by each of said time element devices for effecting energization of the electric lock for said second switch if said trafiic responsive relay is deenergized, means controlled by said first time element device for effecting energization of the .electric look for said first switch, and means controlled 16 by traffic conditions for efiecting energization of both said electric locks if said block is clear and if said track is clear a given distance in the rear of said signal.

13. In combination, a stretch of railway track including a signal block divided into a first and a second section, a signal for governing trafiic movements over said first section and then onto said second section, a stick relay controlled to become energized when a train enters said first section and then to remain energized while said train occupies said second section, a track switch in said second section, a second track switch in said second section farther from said signal than said first switch, an electric lock for each. of said switches each of which when deenergized locks the associated switch in its normal position, a trafiic responsive relay energized when said second section is clear but deenergized when said second section is shunted, means controlled by a front contact of said stick relay for effecting energization of the electric lock for said first switch, a time element device, means controlled by a back contact of said traffic responsive relay for energizing said time element device, a second time element device, means controlled by a front contact of said stick relay for energizing said second time element device, manually controllable means associated with each of said electric locks for shunting the rails of said second section preliminary to unlocking the associated switch, means controlled by each of said time element devices for efiecting energization of the electric lock for said second switch if said traffic responsive relay is deenergized, means controlled by said first time element device for effecting energization of the electric lock for said first switch, means for controlling said signal to display a proceed or a stop indication, and means controlled by traffic conditions for efiecting energization of both said electric looks it said block is clear and if said signal is controlled to display the stop indication.

WARWICK R1. BAKER. ROBERT M. ROSENSTEEL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,404,303 Law July 16, 1946 2,430,314 'Van Horn Nov. 4, 194'? 

